Communication systems such as public address system's often are used by a number of different operators. Misuse of the equipment such as by dropping the microphone, exposure to the elements and overdriving it can degrade performance irrespective that some microphones are predesigned to perform well under these adverse conditions. As a consequence, some of the microphones provide too low an output voltage for satisfactory operation. The microphones need to be tested periodically and, of course, when some do not meet the minimum output requirements, they are replaced.
The conventional testing procedure has been too slow and laborious and has required skilled technicians for this time consuming task. A sound level calibrator has been hand held on the microphone with connector output pins from the microphone clip-connected to a volt meter. Because minimum voltages were required at each of the various frequencies to indicate a satisfactory performance, meter readings were noted and recorded at these frequencies. Because of being hand held and the difficulties of securely affixing monitoring instrumentation, erroneous indications of malfunction could occur since variations of only a few millivolts might be produced that were due to misorientation of the microphone and the interconnected monitoring meter. This could be wasteful since slight millivolt variations could erroneously indicate a defective microphone and the time and effort taken to stabilize the test may not be cost effective.
Thus, there is a continuing need in the state of the art for an in situ microphone test instrumentation that is reliable, not unduly time consuming and may be administered by relatively unskilled technicians.